In applications such as touch screens or display or viewing windows of electronic devices such as liquid crystal displays (LCDs), a glass sheet or substrate is sometimes provided with an antiglare surface, the antiglare properties of the surface are typically provided by a roughened surface, which scatters incident light and thereby reduces glare. The roughened surface is often provided by a polymer film that is applied to a surface of the glass sheet that forms the front of the display. Such antiglare surfaces are often used on the front surfaces of the screens and displays mentioned above to reduce the apparent visibility of external reflections from the display and improve readability of the display under different lighting conditions.
Display “sparkle” or “dazzle” is a phenomenon that can occur when antiglare or light scattering surfaces are incorporated into a display system. Sparkle is associated with a very fine grainy appearance that can appear to have a shift in the pattern of the grains with changing viewing angle of the display. This type of sparkle is observed when pixelated displays such as LCDs are viewed through an antiglare surface. Such sparkle is of a different type and origin from “sparkle” or “speckle” that has been observed and characterized in projection or laser systems.